26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 51 



below represented by row on parafacials descending nearly as low as oral 

 margin, or about half way down, or less than half way, or not descending 

 below base of antennae; or represented only by one or more rows of weak 

 bristly hairs on parafrontals. 



2) Upper fronto-orbital bristles (those on posterior portion of para- 

 frontals immediately in front of the vertical bristles and often appearing as a 

 continuation of frontal rows posteriorly, always reclinate; ascending frontal 

 bristles of Hough) in line with frontal bristles, or with middle fronto-orbital 

 bristles; position, direction, number; or absent. 



2) Middle fronto-orbital bristles (Orbitalborsten of Brauer and v. Berg.; 

 fronto-orbital of Osten-Sacken; orbital bristles of descriptions; they are 

 usually a little nearer the orbit than the preceding, and always proclinate) 

 present in both sexes, or in female only, strong, weak, divergent, convergent ; 

 one, two, three, or a row, or represented only by weak hairs ; or absent in 

 both sexes. 



2) Lower fronto-orbital bristles (lower fronto-orbital of Osten-Sacken 

 and Williston; occurring occasionally in the Acalypterata, but rarely in the 

 Muscoidea) present or absent, number. 



1)2) Parafacials (optica faciei of Rob.-Desv. ; IVangen, gence of Brauer 

 and v. Berg.; sides of face of descriptions; gence of Hough) widened above. 

 or not so ; bare, hairy, bristled ; widened below and narrowed above, more or 

 less swollen, very wide, very narrow, elongate, short; or narrowed, shortened, 

 or abbreviated below. 



2) Facio-orbital bristles (those on parafacials) present or absent, number, 

 position, direction. 



1) Cheeks (peristoma of Rob.-Desv.; Back en, peristoma of Br. and v. 

 Berg. ; buccce of Hough) wide, narrow, very narrow ; width equaling or ex- 

 ceeding eye height, or equaling what proportion of eye height; naked, hairy, 

 bristly, or so only below or behind. [N. B. — Br. and v. Berg, give apparent 

 height (not width) of cheeks as seen in profile, with eyes included. Their 

 actual greatest width (distance from peristomal margin to eye) should be 

 compared with eye height, as seen in front view.] 



1) Cheek margins (portions bordering on parafacials and ptilinal area) 

 ascending, encroaching on face, more or less circumscribing the facial plate. 



2) Cheek grooves (mediana of Rob.-Desv.) present, well defined, curved, 

 wide, deep, shallow, position, vestigial. 



2) Cheek bristles (strong bristles which sometimes occur on cheeks near 

 lower border, slightly outside of peristonialia) present or absent, number, 

 direction, position. 



2) Posterior orbits (bare space between posterior eye margin and row of 

 hairs fringing occiput) widened below, narrowed above, of even width, wide, 

 or narrow. 



2) Lower margin of head (lower border as seen in profile) straight, bulged 

 downward or outward posteriorly, long, short. 



2) Occiput (all the portion of the head behind the plane which defines the 

 limit of the posterior orbits, as marked by the fringe-like row of small bristles 

 or hairs bordering same and called by Hough and others cilia of posterior 

 orbit) evenly swollen, flat ; flat above and swollen below, bulging the cheek 

 profile posteriorly. 



1)2) Parafrontal-occipitai. ridge (ridge-like sclerite formed by what 

 seems a continuation of parafrontals over vertex on occiput and which bifur- 



